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Full-Text Articles in Engineering

Adiabatic Logic-In-Memory Architecture, Himanshu Thapliyal, S. Dinesh Kumar Dec 2020

Adiabatic Logic-In-Memory Architecture, Himanshu Thapliyal, S. Dinesh Kumar

Electrical and Computer Engineering Faculty Patents

An adiabatic logic-in-memory based complementary metal- oxide-semiconductor/magnetic-tunnel-junction (ALiM CMOS/MTJ) circuit utilizes an adiabatic logic based pre- charged sense amplifier (PCSA) to recover energy from its output load capacitors. The ALiM CMOS/MTJ includes a non-volatile magnetic-tunnel-junction (MTJ) based memory. The ALiM CMOS/MTJ also includes a dual rail complementary metal-oxide-semiconductor (CMOS) logic that performs logic operations in association with the MTJ, and thereby generates logic outputs based on logic inputs. The ALiM CMOS/MTJ also includes the adiabatic PCSA, which is operatively coupled to the dual rail CMOS logic. The adiabatic logic based PCSA includes PCSA circuitry for which an input is a …


Experimental And Mathematical Tools To Predict Droplet Size And Velocity Distribution For A Two-Fluid Nozzle, Sadegh Poozesh, Nelson K. Akafuah, Heather R. Campbell, Faezeh Bashiri, Kozo Saito Dec 2020

Experimental And Mathematical Tools To Predict Droplet Size And Velocity Distribution For A Two-Fluid Nozzle, Sadegh Poozesh, Nelson K. Akafuah, Heather R. Campbell, Faezeh Bashiri, Kozo Saito

Mechanical Engineering Faculty Publications

Despite progress in laser-based and computational tools, an accessible model that relies on fundamentals and offers a reasonably accurate estimation of droplet size and velocity is lacking, primarily due to entangled complex breakup mechanisms. Therefore, this study aims at using the integral form of the conservation equations to create a system of equations by solving which, the far-field secondary atomization can be analyzed through predicting droplet size and velocity distributions of the involved phases. To validate the model predictions, experiments are conducted at ambient conditions using water, methanol, and acetone as model fluids with varying formulation properties, such as density, …


Parameter Identification For Cells, Modules, Racks, And Battery For Utility-Scale Energy Storage Systems, Oluwaseun M. Akeyo, Vandana Rallabandi, Nicholas Jewell, Aron Patrick, Dan M. Ionel Nov 2020

Parameter Identification For Cells, Modules, Racks, And Battery For Utility-Scale Energy Storage Systems, Oluwaseun M. Akeyo, Vandana Rallabandi, Nicholas Jewell, Aron Patrick, Dan M. Ionel

Electrical and Computer Engineering Faculty Publications

The equivalent circuit model for utility-scale battery energy storage systems (BESS) is beneficial for multiple applications including performance evaluation, safety assessments, and the development of accurate models for simulation studies. This paper evaluates and compares the performance of utility-scale equivalent circuit models developed at multiple sub-component levels, i.e. at the rack, module, and cell levels. This type of modeling is used to demonstrate that the equivalent circuit model for a reference cell, module, or rack of a BESS can be scaled to represent the entire battery system provided that the battery management system (BMS) is active and functional. Contrary to …


Cost Minimization Of Battery-Supercapacitor Hybrid Energy Storage For Hourly Dispatching Wind-Solar Hybrid Power System, Pranoy Roy, Jiangbiao He, Yuan Liao Nov 2020

Cost Minimization Of Battery-Supercapacitor Hybrid Energy Storage For Hourly Dispatching Wind-Solar Hybrid Power System, Pranoy Roy, Jiangbiao He, Yuan Liao

Electrical and Computer Engineering Faculty Publications

This study demonstrates a dispatching scheme of wind-solar hybrid power system (WSHPS) for a one-hour dispatching period for an entire day utilizing battery and supercapacitor hybrid energy storage subsystem (HESS). A frequency management approach is deployed to extend the longevity of the batteries through extensively utilizing the high energy density property of batteries and the high power density property of supercapacitors in the HESS framework. A low-pass filter (LPF) is employed to decouple the power between a battery and a supercapacitor (SC). The cost optimization of the HESS is computed based on the time constant of the LPF through extensive …


Nmr Spectroscopy Analysis Reveals Differential Metabolic Responses In Arabidopsis Roots And Leaves Treated With A Cytokinesis Inhibitor, Thomas E. Wilkop, Minmin Wang, Angelo Heringer, Jaideep Singh, Florence Zakharov, Viswanathan V. Krishnan, Georgia Drakakaki Nov 2020

Nmr Spectroscopy Analysis Reveals Differential Metabolic Responses In Arabidopsis Roots And Leaves Treated With A Cytokinesis Inhibitor, Thomas E. Wilkop, Minmin Wang, Angelo Heringer, Jaideep Singh, Florence Zakharov, Viswanathan V. Krishnan, Georgia Drakakaki

Physiology Faculty Publications

In plant cytokinesis, de novo formation of a cell plate evolving into the new cell wall partitions the cytoplasm of the dividing cell. In our earlier chemical genomics studies, we identified and characterized the small molecule endosidin-7, that specifically inhibits callose deposition at the cell plate, arresting late-stage cytokinesis in arabidopsis. Endosidin-7 has emerged as a very valuable tool for dissecting this essential plant process. To gain insights regarding its mode of action and the effects of cytokinesis inhibition on the overall plant response, we investigated the effect of endosidin-7 through a nuclear magnetic resonance spectroscopy (NMR) metabolomics approach. In …


An Overview Of Methods And A New Three-Dimensional Fea And Analytical Hybrid Technique For Calculating Ac Winding Losses In Pm Machines, Narges Taran, Dan M. Ionel, Vandana Rallabandi, Greg Heins, Dean Patterson Oct 2020

An Overview Of Methods And A New Three-Dimensional Fea And Analytical Hybrid Technique For Calculating Ac Winding Losses In Pm Machines, Narges Taran, Dan M. Ionel, Vandana Rallabandi, Greg Heins, Dean Patterson

Power and Energy Institute of Kentucky Faculty Publications

This article proposes a new hybrid analytical and numerical finite element (FE) based method for calculating ac eddy current losses in wire windings and demonstrates its applicability for axial flux permanent magnet electric machines. The method takes into account three-dimensional (3-D) field effects in order to achieve accurate results and yet greatly reduce computational efforts. The new 3-D FE-based method is advantageous as it employs minimum simplifications and considers the end turns in the eddy current path, the magnetic flux density variation along the effective length of coils, and the field fringing and leakage, which ultimately increases the accuracy of …


Design Optimization And Comparison Of Direct-Drive Outer-Rotor Srms Based On Fast Current Profile Estimation And Transient Fea, Vandana Rallabandi, Peng Han, Jie Wu, Aaron M. Cramer, Dan M. Ionel, Ping Zhou Oct 2020

Design Optimization And Comparison Of Direct-Drive Outer-Rotor Srms Based On Fast Current Profile Estimation And Transient Fea, Vandana Rallabandi, Peng Han, Jie Wu, Aaron M. Cramer, Dan M. Ionel, Ping Zhou

Power and Energy Institute of Kentucky Faculty Publications

Outer-rotor switched reluctance machines (SRMs) have drawn much attention as promising candidates for in-wheel direct-drive motors of future electric vehicles. This article presents a systematic performance comparison of three outer-rotor SRM topologies for in-wheel traction applications in terms of the specific torque, electromagnetic efficiency, torque ripple, radial force, and mechanical aspects. A generalized design optimization framework for SRMs is proposed to enable the fast evaluation of large numbers of designs generated from the differential evolution by incorporating an analytical current profile estimation into the transient finite element analysis. The relationship between the saliency ratio and converter volt-ampere rating is also …


Evaluation Of Bearing Voltage Reduction In Electric Machines By Using Insulated Shaft And Bearings, Peng Han, Greg Heins, Dean Patterson, Mark Theile, Dan M. Ionel Oct 2020

Evaluation Of Bearing Voltage Reduction In Electric Machines By Using Insulated Shaft And Bearings, Peng Han, Greg Heins, Dean Patterson, Mark Theile, Dan M. Ionel

Power and Energy Institute of Kentucky Faculty Publications

Bearing voltages and corresponding currents in electric machines driven by pulse width modulation (PWM) converters with fast switching and high dv/dt can cause premature bearing failures. This paper evaluates the bearing voltage reduction by using insulated shafts and bearings. An equivalent circuit representation of electric machines taking into account high-frequency effects is developed to show the production mechanism of bearing voltage, based on which simulations are performed with detailed finite element models for transient and simplified equivalent circuit for steady-state analysis. The steady-state equivalent circuit is then calibrated, by combined numerical calculations and experimental measurements, and used to predict the …


Demand Response Of Hvacs In Large Residential Communities Based On Experimental Developments, Huangjie Gong, Evan S. Jones, Rosemary E. Alden, Andrew G. Frye, Donald G. Colliver, Dan M. Ionel Oct 2020

Demand Response Of Hvacs In Large Residential Communities Based On Experimental Developments, Huangjie Gong, Evan S. Jones, Rosemary E. Alden, Andrew G. Frye, Donald G. Colliver, Dan M. Ionel

Power and Energy Institute of Kentucky Faculty Publications

Heating, ventilation, and air-conditioning (HVAC) systems contribute the largest electricity usage for a residential community. Modeling of the HVAC systems facilitate the study of demand response (DR) at both the residential and the power system level. In this paper, the equivalent thermal model of a reference house was proposed. Parameters for the reference house were determined based on the systematic study of experimental data obtained from fully instrumented field demonstrators. The aggregated HVAC load was modeled based on the reference house while considering a realistic distribution of HVAC parameters derived from data that was provided by one of the largest …


Combined Numerical And Experimental Determination Of Ball Bearing Capacitances For Bearing Current Prediction, Peng Han, Greg Heins, Dean Patterson, Mark Theile, Dan M. Ionel Oct 2020

Combined Numerical And Experimental Determination Of Ball Bearing Capacitances For Bearing Current Prediction, Peng Han, Greg Heins, Dean Patterson, Mark Theile, Dan M. Ionel

Electrical and Computer Engineering Faculty Publications

High-frequency voltages across the steel ball bearings and the corresponding currents can cause premature bearing failures in electric machines driven by PWM converters. The bearing voltage, one of the most commonly-used failure indicators, depends heavily on the bearing capacitance. This paper presents a combined numerical and experimental approach for the calculation of ball bearing capacitances to address the uncertainty introduced by lubricant property, lubrication status and other metal parts, such as seals and ball retainers. Based on the obtained capacitance breakdown, the influences of temperature, speed and bearing load (radial, axial or combined) on the capacitance are studied. Measurements and …


Optimal Study Of A High Specific Torque Vernier-Type Axial-Flux Pm Machine With Two Different Stators And A Single Winding, Murat G. Kesgin, Peng Han, Narges Taran, Dan M. Ionel Oct 2020

Optimal Study Of A High Specific Torque Vernier-Type Axial-Flux Pm Machine With Two Different Stators And A Single Winding, Murat G. Kesgin, Peng Han, Narges Taran, Dan M. Ionel

Power and Energy Institute of Kentucky Faculty Publications

This paper presents the optimal study of a verniertype axial-flux permanent-magnet (AFPM) machine, which has a high-polarity spoke-type PM rotor, a wound stator with a low number of coils, and a profiled stator. Both stators have profiled teeth to enhance the magnetic interaction between the rotor PM array and stator windings for torque production. Compared to the topology with two wound stators, the studied one has a smaller total axial length and is expected more suitable for applications where the space is limited in axial direction. Both topologies are optimized through 3-dimensional (3D) finite element analysis (FEA) by the combined …


Electric Power System Studies For A Multi-Mw Pv Farm And Large Rural Community With Net Zero Energy And Microgrid Capabilities, Evan S. Jones, Oluwaseun M. Akeyo, Keith Waters, Dan M. Ionel Oct 2020

Electric Power System Studies For A Multi-Mw Pv Farm And Large Rural Community With Net Zero Energy And Microgrid Capabilities, Evan S. Jones, Oluwaseun M. Akeyo, Keith Waters, Dan M. Ionel

Power and Energy Institute of Kentucky Faculty Publications

Solar photovoltaic (PV) systems are currently being deployed at an accelerated rate because of their cost-competitiveness and environmental benefits, which make them a prime candidate for local renewable energy generation in communities. Microgrids can help accommodate for the problems that accompany PV systems, such as intermittency due to weather, by coordinating different distributed energy resources (DERs), while islanded or by drawing power from the utility while in grid-connected mode. An islanding option is also important for resilience and grid fault mitigation, even if other DERs are not present within the system. This paper studies the potential benefits that a multi-MW …


Electric Drives With Wide Bandgap Devices For Two-Phase Very Low Inductance Machines, Yibin Zhang, Damien Lawhorn, Peng Han, Aaron M. Cramer, Dan M. Ionel Oct 2020

Electric Drives With Wide Bandgap Devices For Two-Phase Very Low Inductance Machines, Yibin Zhang, Damien Lawhorn, Peng Han, Aaron M. Cramer, Dan M. Ionel

Power and Energy Institute of Kentucky Faculty Publications

Slotless and coreless machines with low inductance and low core losses are attractive for high speed and high power density applications. With the increase in fundamental frequency, typical drive implementations using conventional silicon-based devices are performance limited and also produce large current and torque ripples. This paper presents a systematic study of proposed drive configurations implemented with wide bandgap (WBG) devices in order to mitigate such issues for 2-phase very low inductance machines. Two inverter topologies, i.e., a dual H-bridge inverter with maximum redundancy and survivability and a 3-leg inverter for reduced cost, are considered. Feasible modulation schemes are derived …


Design Optimization Of Coreless Axial-Flux Pm Machines With Litz Wire And Pcb Stator Windings, Murat G. Kesgin, Peng Han, Narges Taran, Damien Lawhorn, Donovin Lewis, Dan M. Ionel Oct 2020

Design Optimization Of Coreless Axial-Flux Pm Machines With Litz Wire And Pcb Stator Windings, Murat G. Kesgin, Peng Han, Narges Taran, Damien Lawhorn, Donovin Lewis, Dan M. Ionel

Electrical and Computer Engineering Faculty Publications

Coreless axial-flux permanent-magnet (AFPM) machines may be attractive options for high-speed and high-power-density applications due to the elimination of core losses. In order to make full use of the advantages offered by these machines and avoid excessive eddy current losses in windings, advanced technologies for winding conductors need to be employed to suppress the eddy effect, such as the Litz wire and printed circuit board (PCB). In this paper, the best practices for designing Litz wire/PCB windings are discussed and a brief survey of state of the art PCB winding technology is provided. Three coreless AFPM machines are mainly considered. …


Survey Of Dc-Dc Non-Isolated Topologies For Unidirectional Power Flow In Fuel Cell Vehicles, Mahajan Sagar Bhaskar, Vigna K. Ramachandaramurthy, Sanjeevikumar Padmanaban, Frede Blaabjerg, Dan M. Ionel, Massimo Mitolo, Dhafer Almakhles Sep 2020

Survey Of Dc-Dc Non-Isolated Topologies For Unidirectional Power Flow In Fuel Cell Vehicles, Mahajan Sagar Bhaskar, Vigna K. Ramachandaramurthy, Sanjeevikumar Padmanaban, Frede Blaabjerg, Dan M. Ionel, Massimo Mitolo, Dhafer Almakhles

Power and Energy Institute of Kentucky Faculty Publications

The automobile companies are focusing on recent technologies such as growing Hydrogen (H2) and Fuel Cell (FC) Vehicular Power Train (VPT) to improve the Tank-To-Wheel (TTW) efficiency. Benefits, the lower cost, `Eco' friendly, zero-emission and high-power capacity, etc. In the power train of fuel cell vehicles, the DC-DC power converters play a vital role to boost the fuel cell stack voltage. Hence, satisfy the demand of the motor and transmission in the vehicles. Several DC-DC converter topologies have proposed for various vehicular applications like fuel cell, battery, and renewable energy fed hybrid vehicles etc. Most cases, the DC-DC power converters …


100% Renewable Energy Grid For Rural Electrification Of Remote Areas: A Case Study In Jordan, Loiy Al-Ghussain, Mohammad Abujubbeh, Adnan Darwish Ahmad, Ahmad M. Abubaker, Onur Taylan, Murat Fahrioglu, Nelson K. Akafuah Sep 2020

100% Renewable Energy Grid For Rural Electrification Of Remote Areas: A Case Study In Jordan, Loiy Al-Ghussain, Mohammad Abujubbeh, Adnan Darwish Ahmad, Ahmad M. Abubaker, Onur Taylan, Murat Fahrioglu, Nelson K. Akafuah

Institute of Research for Technology Development Faculty Publications

Many developing countries suffer from high energy-import dependency and inadequate electrification of rural areas, which aggravates the poverty problem. In this work, Al-Tafilah in Jordan was considered as a case study, where the technical, economic, and environmental benefits of a decentralized hybrid renewable energy system that can match 100% of the city demand were investigated. A tri-hybrid system of wind, solar, and hydropower was integrated with an energy storage system and optimized to maximize the match between the energy demand and production profiles. The optimization aimed at maximizing the renewable energy system (RES) fraction while keeping the levelized cost of …


Measurement Of Three-Dimensional Welding Torch Orientation For Manual Arc Welding Process, Yuming Zhang, Weijie Zhang Sep 2020

Measurement Of Three-Dimensional Welding Torch Orientation For Manual Arc Welding Process, Yuming Zhang, Weijie Zhang

Electrical and Computer Engineering Faculty Patents

Methods and systems are provided herein for measuring 3D apparatus (e.g., manual tool or tool accessory) orientation. Example implementations use an auto-nulling algorithm that incorporates a quaternion-based unscented Kalman filter. Example implementations use a miniature inertial measurement unit endowed with a tri-axis gyro and a tri-axis accelerometer. The auto-nulling algorithm serves as an in-line calibration procedure to compensate for the gyro drift, which has been verified to significantly improve the estimation accuracy in three-dimensions, especially in the heading estimation.


The Effect Of High Efficiency Building Technologies And Pv Generation On The Energy Profiles For Typical Us Residences, Evan S. Jones, Rosemary E. Alden, Huangjie Gong, Andrew G. Frye, Donald G. Colliver, Dan M. Ionel Sep 2020

The Effect Of High Efficiency Building Technologies And Pv Generation On The Energy Profiles For Typical Us Residences, Evan S. Jones, Rosemary E. Alden, Huangjie Gong, Andrew G. Frye, Donald G. Colliver, Dan M. Ionel

Power and Energy Institute of Kentucky Faculty Publications

The penetrations of high efficiency technologies and photovoltaic (PV) generation are increasing in the residential sector. Technologies such as improved insulation and efficient HVAC systems significantly affect the energy profile of a house. This effect varies due to climate characteristics, i.e. temperature, solar radiation, relative humidity, and wind speeds. The effect of other technologies, such as efficient water heaters, lighting, or kitchen appliances, is mainly governed by human behavior, which may be represented by a schedule. This paper studies the performance of both climate-influenced and scheduled household devices among different levels of efficiency through combined computational and experimental methods. Three …


On The Feasibility Of Electrification For Large Mobile Cranes, Donovin Lewis, Damien Lawhorn, Dan M. Ionel Sep 2020

On The Feasibility Of Electrification For Large Mobile Cranes, Donovin Lewis, Damien Lawhorn, Dan M. Ionel

Power and Energy Institute of Kentucky Faculty Publications

Trends towards vehicle electrification to reduce dependence on fossil fuels and increase drive train efficiency have led vehicle manufacturers to seek out paths towards gradual hybridization. For heavy duty construction vehicles, electrification consists of two principle components: electric hybridization of the vehicle carrier and the vehicle's auxiliary function. Economic and physical feasibility for the transition to electrical replacements for critical system components is important for the gradual development of electrified systems. In this paper, we present an investigation into multiple pathways for the hybridization of mobile cranes paired with simulations that analyze the feasibility of system electrification. ADVISOR was used …


Lstm Forecasts For Smart Home Electricity Usage, Rosemary E. Alden, Huangjie Gong, Cristinel Ababei, Dan M. Ionel Sep 2020

Lstm Forecasts For Smart Home Electricity Usage, Rosemary E. Alden, Huangjie Gong, Cristinel Ababei, Dan M. Ionel

Power and Energy Institute of Kentucky Faculty Publications

With increasing of distributed energy resources deployment behind-the-meter and of the power system levels, more attention is being placed on electric load and generation forecasting or prediction for individual residences. While prediction with machine learning based approaches of aggregated power load, at the substation or community levels, has been relatively successful, the problem of prediction of power of individual houses remains a largely open problem. This problem is harder due to the increased variability and uncertainty in user consumption behavior, which make individual residence power traces be more erratic and less predictable. In this paper, we present an investigation of …


A Hybrid Achromatic Metalens, Fatih Balli, Mansoor A. Sultan, Sarah K. Lami, J. Todd Hastings Aug 2020

A Hybrid Achromatic Metalens, Fatih Balli, Mansoor A. Sultan, Sarah K. Lami, J. Todd Hastings

Electrical and Computer Engineering Faculty Publications

Metalenses, ultra-thin optical elements that focus light using subwavelength structures, have been the subject of a number of recent investigations. Compared to their refractive counterparts, metalenses offer reduced size and weight, and new functionality such as polarization control. However, metalenses that correct chromatic aberration also suffer from markedly reduced focusing efficiency. Here we introduce a Hybrid Achromatic Metalens (HAML) that overcomes this trade-off and offers improved focusing efficiency over a broad wavelength range from 1000-1800 nm. HAMLs can be designed by combining recursive ray-tracing and simulated phase libraries rather than computationally intensive global search algorithms. Moreover, HAMLs can be fabricated …


An Aggregated And Equivalent Home Model For Power System Studies With Examples Of Building Insulation And Hvac Control Improvements, Huangjie Gong, Evan S. Jones, Dan M. Ionel Aug 2020

An Aggregated And Equivalent Home Model For Power System Studies With Examples Of Building Insulation And Hvac Control Improvements, Huangjie Gong, Evan S. Jones, Dan M. Ionel

Power and Energy Institute of Kentucky Faculty Publications

Introducing new technologies into existing residences provides opportunities for the utility to enhance a community's power system performance. To validate the benefits of such technologies, an energy model is required in which their integration with a community's power system may be simulated. It can be difficult or impossible to properly model a power system without sufficient sample data. This paper proposes a method that uses Gaussian kernel density estimation (GKDE) to calculate the aggregated net power flow of a community's distribution system with only limited sample points at each time step. Example case studies that confirm the usefulness of the …


Techno-Economic Comparative Analysis Of Renewable Energy Systems: Case Study In Zimbabwe, Loiy Al-Ghussain, Remember Samu, Onur Taylan, Murat Fahrioglu Jul 2020

Techno-Economic Comparative Analysis Of Renewable Energy Systems: Case Study In Zimbabwe, Loiy Al-Ghussain, Remember Samu, Onur Taylan, Murat Fahrioglu

Mechanical Engineering Graduate Research

Fluctuations in fossil fuel prices significantly affect the economies of countries, especially oil-importing countries, hence these countries are thoroughly investigating the increase in the utilization of renewable energy resources as it is abundant and locally available in all the countries despite challenges. Renewable energy systems (RES) such as solar and wind systems offer suitable alternatives for fossil fuels and could ensure the energy security of countries in a feasible way. Zimbabwe is one of the African countries that import a significant portion of its energy needs which endanger the energy security of the country. Several studies in the literature discussed …


Dynamic Modeling And Optimal Design For Net Zero Energy Houses Including Hybrid Electric And Thermal Energy Storage, Huangjie Gong, Vandana Rallabandi, Dan M. Ionel, Donald G. Colliver, Shaun Duerr, Cristinel Ababei Jul 2020

Dynamic Modeling And Optimal Design For Net Zero Energy Houses Including Hybrid Electric And Thermal Energy Storage, Huangjie Gong, Vandana Rallabandi, Dan M. Ionel, Donald G. Colliver, Shaun Duerr, Cristinel Ababei

Power and Energy Institute of Kentucky Faculty Publications

Net zero energy (NZE) houses purchase zero net metered electricity from the grid over a year. Technical challenges brought forth by NZE homes are related to the intermittent nature of solar generation, and are due to the fact that peak solar generation and load are not coincident. This leads to a large rate of change of load, and in case of high PV penetration communities, often requires the installation of gas power plants to service this variability. This paper proposes a hybrid energy storage system including batteries and a variable power electric water heater which enables the NZE homes to …


System, Device, And Method For Determination Of Intraocular Pressure, Jeffrey Todd Hastings, E. Britt Brockman, Ingrid L. St. Omer, John C. Wright Jun 2020

System, Device, And Method For Determination Of Intraocular Pressure, Jeffrey Todd Hastings, E. Britt Brockman, Ingrid L. St. Omer, John C. Wright

Electrical and Computer Engineering Faculty Patents

A system for determination of intraocular pressure includes: an intraocular pressure sensor; a light source illuminating the sensor with one or more wavelengths of light; and a detector that measures emitted light from the sensor. The sensor includes a substrate member, a spacer member, and a flexible membrane, which define a sealed cavity. The flexible membrane moves in response to intraocular pressure changes. A device for measuring intraocular pressure includes: the sensor; an anchoring member attached to the sensor for immobilizing the sensor in an eye; and a protective member attached to the anchoring member and covering the sensor to …


A Network Graph Technique For The Design Of Electric Aircraft Power Systems, Damien Lawhorn, Vandana Rallabandi, Dan M. Ionel Jun 2020

A Network Graph Technique For The Design Of Electric Aircraft Power Systems, Damien Lawhorn, Vandana Rallabandi, Dan M. Ionel

Power and Energy Institute of Kentucky Faculty Publications

Today the electrification of flight is more popular than ever, creating a wide array of concept aircraft and associated power system topologies. In order to gain insights into benefits of these varying architectures, this paper introduces the development of a framework for electric aircraft power system (EAPS) optimization. The proposed framework accepts inputs from a designer in the form of component parameters and desired flight mission characteristics. A collective graph representing many architectures is formed, from which, subgraphs or power system topologies meeting the flight requirements are extracted and analyzed. An optimum topology meeting the flight requirements with minimum mass, …


Optimization Of Aggregated Ev Power In Residential Communities With Smart Homes, Huangjie Gong, Dan M. Ionel Jun 2020

Optimization Of Aggregated Ev Power In Residential Communities With Smart Homes, Huangjie Gong, Dan M. Ionel

Power and Energy Institute of Kentucky Faculty Publications

Electric vehicles (EVs) tend to increase peak power for residences in the evening when house owners return home and begin charging. The aggregated EV charging demand can cause a sudden rise in the peak power at the distribution system level, resulting in a “dragon curve” Such phenomenon, combined with the “duck curve” that is caused by high photovoltaic (PV) penetration in residential communities, requires fast ramping rates and expanded capabilities for local distribution transformers and main feeder cables provided by the utility. As a solution, a residential energy storage system (RESS) can store surplus PV generation during midday and use …


Analysis And Investigation Of Hybrid Dc–Dc Non-Isolated And Non-Inverting Nx Interleaved Multilevel Boost Converter (Nx-Imbc) For High Voltage Step-Up Applications: Hardware Implementation, Mahajan Sagar Bhaskar, Dhafer J. Almakhles, Sanjeevikumar Padmanaban, Frede Blaabjerg, Umashankar Subramaniam, Dan M. Ionel May 2020

Analysis And Investigation Of Hybrid Dc–Dc Non-Isolated And Non-Inverting Nx Interleaved Multilevel Boost Converter (Nx-Imbc) For High Voltage Step-Up Applications: Hardware Implementation, Mahajan Sagar Bhaskar, Dhafer J. Almakhles, Sanjeevikumar Padmanaban, Frede Blaabjerg, Umashankar Subramaniam, Dan M. Ionel

Power and Energy Institute of Kentucky Faculty Publications

In significant cases, the generated voltage needs to be step-up with high conversion ratio by using the DC-DC converter as per the requirement of the load. The drawbacks of traditional boost converter are it required high rating semiconductor devices and have high input current ripple, low efficiency, and reverse recovery voltage of the diodes. Recently, the family of Multilevel Boost Converter suggested and suitable configuration to overcome the above drawbacks. In this article, hybrid DC-DC non-isolated and non-inverting Nx Interleaved Multilevel Boost Converter (Nx-IMBC) is analyzed in Continuous Conduction Mode (CCM) and Discontinuous Conduction Mode (DCM) with boundary condition and …


The Design And Analysis Of Large Solar Pv Farm Configurations With Dc Connected Battery Systems, Oluwaseun M. Akeyo, Vandana Rallabandi, Nicholas Jewell, Dan M. Ionel May 2020

The Design And Analysis Of Large Solar Pv Farm Configurations With Dc Connected Battery Systems, Oluwaseun M. Akeyo, Vandana Rallabandi, Nicholas Jewell, Dan M. Ionel

Power and Energy Institute of Kentucky Faculty Publications

Typically, solar inverters curtail or “clip” the available power from the PV system when it exceeds the maximum ac capacity. This paper discusses a battery system connected to the dc-link of an inverter to recuperate this PV energy. Contrary to conventional approaches, which employ two dc-dc converters, one each for the battery and solar PV system, the proposed configuration utilizes a single dc-dc converter capable of simultaneously operating as a charge controller and a maximum power point tracking (MPPT) tracking device. In addition to improving the overall system capacity factor, increasing the conversion efficiencies and ensuring MPPT stability, the proposed …


Evaluating The Effects Of Electric And Magnetic Loading On The Performance Of Single And Double Rotor Axial Flux Pm Machines, Narges Taran, Greg Heins, Vandana Rallabandi, Dean Patterson, Dan M. Ionel Apr 2020

Evaluating The Effects Of Electric And Magnetic Loading On The Performance Of Single And Double Rotor Axial Flux Pm Machines, Narges Taran, Greg Heins, Vandana Rallabandi, Dean Patterson, Dan M. Ionel

Power and Energy Institute of Kentucky Faculty Publications

Axial flux PM (AFPM) machines are used particularly in applications requiring a compact structure. Their disc shape topology and axial air-gap have led to a variety of configurations including two popular ones: the yokeless and segmented armature (YASA), and the single-stator single rotor or single sided machine. In this study, a comprehensive comparative analysis of these configurations is conducted at different magnetic and electric loadings. It is found that at lower loadings, typically employed for air-cooled machines, the torque/ampere characteristics of the YASA machine are almost identical to those of a single sided machine constructed with half the magnet volume. …